• 기술혁신학회지
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• 제16권3호
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• pp.724-753
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• 2013

본 연구는 중소벤처 녹색전문기업의 녹색기술 특허가 재무성과에 반영되는가를 살펴보았다. 중소벤처 녹색전문기업이 녹색기술로 취득한 녹색기술 특허의 특허출원 1년 전과 1년 후 및 2년 후에 대해 매출액, 영업이익, 순이익, 매출액영업이익률, 매출액순이익률을 선정하여 평균차이 분석을 수행하였다. 실증분석결과 중소벤처 녹색전문기업의 1,2년 후의 매출액과 1년 후의 영업이익과 매출액순이익률 및 2년 후의 매출액영업이익률만 증가하는 것으로 나타났다. 이러한 연구결과에 따라 정부는 중소벤처 녹색전문기업을 향후 녹색성장 시대의 국가경제의 핵심역할을 할 수 있도록 육성하기 위해서 녹색소비 시장의 활성화, 녹색금융정책의 강화, 자금조달 창구 개선 및 마련, 대중소기업 공정거래 및 상생협력 수준을 강화시킬 필요가 있다.

• 대한기계학회논문집A
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• 제39권6호
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• pp.561-566
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• 2015

본 논문에서는 고 중량물을 빠르게 이송시키며'Pick & Place'작업을 수행하는 병렬로봇의 작동강성 최적설계에 대한 연구를 수행하였다. 20~30kg 의 고 중량물을 사용하여 특정 작업을 빠르게 수행하기 위해서는 빠른 응답속도를 위한 관성 기구부 경량 설계와 동시에 동작의 정밀도를 위한 고 강성설계가 필요하다. 하지만 요구조건인 관성 기구부 경량 설계와 고강성 설계는 상호 배타적인 관계이므로 본 연구에서는 다물체동역학 해석을 통해서 병렬로봇의 동적 거동을 분석함으로써 로봇의 작동 중에 작용하는 하중상태를 분석하였고, 상호 배타적인 두 성능을 동시에 만족시키기 위해 관성 기구부 위상 최적 설계를 수행하였다. 그리고 위상 최적설계 결과를 병렬로봇에 적용하여 그 신뢰성을 검증하였다.

• Nuclear Engineering and Technology
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• 제52권9호
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• pp.2009-2016
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• 2020

A nuclear power plant is a large complex system with tens of thousands of components. To ensure plant safety, the early and accurate diagnosis of abnormal situations is an important factor. To prevent misdiagnosis, operating procedures provide the anticipated symptoms of abnormal situations. While the more severe emergency situations total less than ten cases and can be diagnosed by dozens of key plant parameters, abnormal situations on the other hand include hundreds of cases and a multitude of parameters that should be considered for diagnosis. The tasks required of operators to select the appropriate operating procedure by monitoring large amounts of information within a limited amount of time can burden operators. This paper aims to develop a system that can, in a short time and with high accuracy, select the appropriate operating procedure and sub-procedure in an abnormal situation. Correspondingly, the proposed model has two levels of prediction to determine the procedure level and the detailed cause of an event. Simulations were conducted to evaluate the developed model, with results demonstrating high levels of performance. The model is expected to reduce the workload of operators in abnormal situations by providing the appropriate procedure to ultimately improve plant safety.

• 한국생산제조학회지
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• 제26권2호
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• pp.243-250
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• 2017

A numerical study was conducted to calculate the cooling capacity variation of a power plant ACC (air-cooled condenser) caused by changes in operating conditions. A numerical model was developed using the ${\varepsilon}-NTU$ and finite volume method, containing 100 elements for a single low fin tube. The model was validated through a comparison of cooling capacity between the simulated values and manufacturer's data. Even though simple assumptions and previously presented heat transfer correlations were applied to the model, the prediction error was 1.9%. The simulated variables of the operating conditions were air velocity, air temperature, and mass flux. The analysis on the variation of thermal resistance along the tube showed that the water side thermal resistance was higher than the air side thermal resistance at the downstream end of the tube, indicating that the ACC capacity could be increased by applying technology to enhance in-tube flow condensation heat transfer.

• 수산해양기술연구
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• 제49권1호
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• pp.40-50
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• 2013

This study is aimed to find a control factor for the marine casualty of fishing vessel by using the risk quantitative method of marine casualty, and sequentially timed event analysis for the reason finding. The result is that collision, sinking, and capsizing took high risk need to be strongly controlled. And the accident reason and control factors distinguished are as follows. The 82.2% of collided fishing vessels have negligence of look out as a immediate cause, while it was judged that underlying causes were the characteristics of vessels and fishing method, lack of suitable complement, fatigue, the prejudice or ignorance on steering and sailing rules. So the control factors are; firstly needs educational control measures and in terms of systemic control approach expand the range of the certificate of competency more smaller tonnage.

• Nuclear Engineering and Technology
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• 제55권9호
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• pp.3164-3182
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• 2023

The CRUD on the fuel cladding under the pressurized water reactor (PWR) operating condition causes several issues. The CRUD can act as thermal resistance and increases the local cladding temperature which accelerate the corrosion process. The hideout of boron inside the CRUD results in axial offset anomaly and reduces the plant's shutdown margin. Recently, there are efforts to revise the acceptance criteria of emergency core cooling systems (ECCS), and additionally require the modeling of the thermal resistance effect of the CRUD during the performance analysis. There is an urgent need for the evaluation of the effect of the CRUD deposition on the cladding heat transfer under PWR operating conditions, but the experimental database is very limited. The experimental facility called DISNY was designed and constructed to analyze the CRUD-related multi-physical phenomena, and the performance analysis of the constructed DISNY facility was conducted. The thermal-hydraulic and water chemistry conditions to simulate the CRUD growth under PWR operating conditions were established. The design characteristics and feasibility of the DISNY facility were validated by the MARS-KS code analysis and separate performance tests. In the current study, detailed design features, design validation results, and future utilization plans of the proposed DISNY facility are presented.

• Nuclear Engineering and Technology
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• 제56권5호
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• pp.1698-1711
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• 2024

Heat pipe cooled reactors have gained attention as a potential solution for nuclear power generation in space and deep sea applications because of their simple design, scalability, safety and reliability. However, under complex operating conditions, a control strategy for variable load operation is necessary. This paper presents a two-dimensional transient characteristics analysis program for a heat pipe cooled reactor and proposes a variable load control strategy using the recuperator bypass (CSURB). The program was verified against previous studies, and steady-state and step-load operating conditions were calculated. For normal operating condition, the predicted temperature distribution with constant heat pipe temperature boundary conditions agrees well with the literature, with a maximum temperature difference of 0.4 K. With the implementation of the control strategy using the recuperator bypass (CSURB) proposed in this paper, it becomes feasible to achieve variable load operation and return the system to a steady state solely through the self-regulation of the reactor, without the need to operate the control drum. The average temperature difference of the fuel does not exceed 1 % at the four power levels of 70 %,80 %, 90 % and 100 % Full power. The output power of the turbine can match the load change process, and the temperature difference between the inlet and outlet of the turbine increases as the power decreases.

• 한국신뢰성학회지:신뢰성응용연구
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• 제8권3호
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• pp.135-144
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• 2008

The economic life for three types of military wheeled vehicles with load capacities of 1/4, $1{\cdot}1/4$, and $2{\cdot}1/2$ tones has been evaluated on the basis of the equivalent acquisition and operating costs. The economic life of wheeled vehicles were calculated from 12 to 18 years by using the annual equivalent cost method. The equivalent cost was decided at the lowest point of the total amount of equivalent acquisition cost and operating cost. The operating cost were collected from the field data. The evaluated economic life can be very useful for deciding the total life cycle of these three types of military vehicles. The annual equivalent cost method may be also applied to other military equipments such as communication electronics, weapon systems, and other type of vehicles.

• Journal of Advanced Marine Engineering and Technology
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• 제8권2호
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• pp.74-80
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• 1984

In the reduction gears for marine propulsion engine such as turbine or high speed diesel engine, the standard involute double helical gears are generally used. However the addendum modification gear can be used in the reduction gear as it has flexibility for gear design on the tooth strength, scoring and operating noise. In this case, the determination of gear shaft bearing load is difficult by the alternation of operating pressure angle. In this paper, the formulas of bearing load according to the arrangements of the reduction gears are derived and the diagrams of operating pressure angle according to the modification coefficient are presented.

• 정보화정책
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• 제23권1호
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• pp.38-55
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• 2016

본 연구는 윈도우 사용자가 구 버전의 운영체제를 상위 버전으로 업그레이드하는 동기에 대해 논의한다. 본 연구문제를 논의하기 위해 통합기술수용이론(UTAUT)과 합리적 행위이론(TRA)을 바탕으로 연구가설을 구성했다. 대학생을 대상으로 199부의 데이터를 수집해 분석에 이용했다. 분석결과는 두 가지로 요약된다. 첫째, 성과기대와 노력기대는 운영체제 업그레이드 태도에 긍정적인 영향을 미치는 것으로 나타났다. 둘째, 사회적 영향과 용이한 조건, 그리고 태도는 운영체제 업그레이드 의도에 긍정적인 영향을 미쳤다. 따라서 사용자의 성과기대, 노력기대, 사회적 영향, 그리고 용이한 조건 인식이 높을수록 상위 버전으로 업그레이드하고자 하는 의도는 더욱 긍정적으로 평가한다고 볼 수 있다.